Chronic renal failure associated with vesico-ureteral reflux related nephropathy accounts for at least 5 and possibly as many as 15% of patients with end stage renal disease. Whether corrective surgery or prophylactic therapy of urinary tract infection represents the best approach to the prevention of renal damage remains controversial. The study described, based on random allocation of patients with Gr. III vesico-ureteral reflux (Dwoskin-Perlmutter classification) to either medical or surgical therapy, will permit us to compare the effect of each of these therapeutic modalities on a) rate of renal growth, b) development of new scars, c) progression of established scars, d) emergent rates of recurrent infections, e) incidence of hypertension. Well defined methods of patient selection and of initial and follow-up radiological and functional examination establish the premise for generation of meaningful information. Since the study is confined to Grade III reflux in children less than 9 years old and excludes duplicate collecting systems, the potential patient pool is limited to less than 10% of the reflux population. To generate statistically significant data in a reasonable time frame, collaboration between large numbers of referral centers both in the United States and Europe is necessary. The patient populatton is projected to total 400 children. Three hundred patients will be provided by 15 institutions in the United States and 100 patients from the European clinics. An identical protocol will be followed in parallel by the European clinics. The results will be analyzed both on separate and pooled data.